1987 NISSAN PULSAR service

Fuel and Engine Management 93
liter engines, or the throttle body hose fitting on 1.6
liter engines.

(5) Tighten all connectors securely. Check for
external leaks as previously described. (6) Start the engine and note the pressure while
the engine is idling.
(7) Switch the engine Off and check that the
residual pressure does not decrease.
If the fuel pressure is within Specifications and
does not decrease, the fuel system is in a serviceable
condition. Depressurize the fuel system and discon-
nect the pressure gauge.

If the fuel pressure is a bove Specifications proceed
to operation (9).

If the fuel pressure is below Specifications proceed
to the following operation.

If the fuel pressure decreases, an internal leak is
indicated. Proceed to the following heading and carry
out the test procedure.


Testing the fuel system pressure using a pressure
gauge. 1.8 liter engine.
NOTE: There may be a small initial de-
crease in pressure when the engine is
switched Off This is acceptable and does not
indicate a fault in the system.

(8) If the fuel pressure is below Specifications
proceed as follows:

(a) Check the fuel lines for blockages and kinks
or a blocked fuel filter or fuel pump pickup strainer. (b) If no fault can be found in the previous
checks, on 1.8 liter engines clamp the fuel return hose
at the fuel rail. On 1.6 liter engines, clamp the hose that is
connected to the front throttle body hose fitting.

(c) Connect a jumper lead between terminals G
and H on the diagnostic link connector and switch the
ignition On.

NOTE: Do not operate the fuel pump for
longer than is necessary to obtain a pressure
reading.

If the fuel pressure is less than 270 kPa on 1.8 liter
engines or 90 kPa on 1.6 liter engines, renew the fuel
pump.

If the fuel pressure is more than previously
specified, renew the pressure regulator assembly on
1.8 liter engines or the pressure regulator diaphragm
on 1.6 liter engines.

(9) If the fuel pressure in operation (6) is above
Specifications, proceed as follows:

(a) On 1.8 liter engines, disconnect the fuel
return hose from the pressure regulator outlet.

On 1.6 liter engines, disc onnect the fuel return
hose from the front throttle body hose fitting.

(b) Connect a suitable length of fuel hose to the
pressure regulator or the front throttle body hose
filling and place the opposite end of the hose into a
petroleum resistant container. (c) Connect a jumper lead between terminals G
and H on the diagnostic link connector and switch the
ignition On. If the fuel pressure is 230-270 kPa on 1.8 liter
engines or 62-90 kPa on 1.6 liter engines, locate and
remove the restriction in the fuel return hose or pipe.

If the fuel pressure is more than previously
specified, renew the pressure regulator assembly on
1.8 liter engines or the pressure regulator diaphragm
on 1.6 liter engines.

TO TEST FOR INTERNAL FUEL LEAKAGE
Check the residual fuel pressure as previously
described.

If the pressure has decreased it is an indication of
an internal leak. With the pressure gauge still at-
tached, proceed as follows:

(1) Switch the ignition On to pressurize the fuel
system.
(2) As the pressure begins to decrease clamp the
fuel supply hose shut. If the pressure remains steady
the fuel pump may be consid ered faulty and should be
renewed as described later in this section. (3) If the pressure continues to decrease switch
the ignition On after it has been Off at least 10
seconds. As the pressure begi ns to decrease clamp the
fuel return hose shut. If the pressure remain steady on 1.8 liter engines,
renew the pressure regulator. If the pressure continues
to decrease, leaking inject ors are indicated. Remove
the injectors as described later in this section to locate
the leaking injectors.

If the pressure remains stea dy on 1.6 liter engines,
renew the pressure regulator diaphragm as described
later in this section. If the pressure continues to
decrease remove the injector and renew the O ring
seals as described later in this section. If this fails to
rectify the fault remove the injector and clean or
renew the injector as necessary.

Fuel and Engine Management 95
(3) Disconnect the vacuum hose from the pres-
sure regulator.
(4) Release the fuel hose clamps, disconnect the
hoses from the pressure regulator and remove the
pressure regulator. Installation is a reversal of the removal procedure
ensuring that the fuel hose clamps are tightened
securely.

To Remove and Install — 1.6 Liter Engine
(1) Depressurize the fuel system as previously
described. (2) Disconnect the negative battery terminal.
(3) Remove the air cleaner assembly. If neces-
sary, refer to the Air Cleane r Assembly heading in this
section. (4) Remove the screws securing the pressure
regulator cover to the throttle body assembly. When removing the final screw hold the cover
firmly as it is under spring tension.

(5) Remove the cover, spring seat, spring and
diaphragm from the thrott le body assembly. Discard
the diaphragm.


View of the pressure regulator components removed
from the throttle body assembly. 1.6 liter engine.
Installation is a reversal of the removal procedure
with attention to the following points:

(1) Install a new diaphragm ensuring that
the
diaphragm is correctly seat ed in the groove in the
throttle body assembly. (2) Apply Loctite 262 to the threads of the
retaining screws.
(3) Place the spring seat and the spring in the
cover and install the cover to the throttle body
assembly, ensuring that the cover is positioned on the
locating dowels. (4) While holding the cover in position install
the
retaining screws and tighten securely.
NOTE: When installing the pressure regu-
lator cover ensure that the diaphragm is not
disturbed, to prevent the possibility of a fuel
leak.

INJECTORS
To Test Injector Circuit and Injectors
(1) Disconnect the injector wiring connectors.
(2) Connect a test lamp between the injector
wiring connector terminals, ensuring that the test
lamp probes do not contact each other. (3) With the ignition switched On the test lamp
should not light. On 1.8 liter engines, check each of
the other connectors.
If the test lamp lights check the wiring harness for
a short to earth between the injector wiring connec-
tor(s) and the control unit wiring connector termi-
nal - D15 and D16 on 1.8 liter engines, or D16 on
1.6 liter engines.

(4) With the aid of an assistant, operate the
starter motor. The test lamp should flash. On 1.8 liter
engines, check each of the other connectors.

If the test lamp does not flash when connected to
the injector wiring connecto r(s), proceed to operation
(6).

If the test lamp lights as described, proceed as
follows.

If the test lamp lights but fails to flash, a faulty
control unit is indicated. Pr ior to renewing the control
unit, check the condition of the injectors as follows.

(5) Connect an ohmmeter between the terminals
of the injectors).

The resistance should be more than 1.2 ohms on
1.6 liter engines or more than 12 ohms on 1.8 liter
engines.

If the injector resistance is as specified, the
injector circuit can be considered serviceable.

If the injector resistance is not as specified, renew
the faulty injector(s).

(6) With the ignition switched On, probe the
injector wiring connector terminals with a test lamp to
earth.

If the test lamp lights when the probe contacts the
pink wire terminal on 1.6 liter engines, or the white
wire terminal on 1.8 liter engines, check the wiring
harness for a short to volt age between the injector
wiring connector(s) and the control unit wiring con-
nector terminal(s) D16 on 1.6 liter engines, or D15
and D16 on 1.8 liter engines.

If the test lamp does not light when the probe
contacts the blue wire termin al on 1.6 liter engines, or
the black and red wire term inal on 1.8 liter engines,
check the EGI relay and circ uit as described under the
EG! and Fuel Pump Relays heading in this section.

If the test lamp lights when the probe contacts the
blue wire terminal on 1.6 lite r engines, or the blue and
red wire terminal on 1.8 liter engines, proceed as
follows.

(7) Switch the ignition Off and connect the
injector wiring connectors). (8) Switch the ignition On and, using a test lamp
to earth, backprobe the cont rol unit wiring connector

104 Fuel and Engine Management

(3) Gently pull the outer throttle cable until the
inner cable remains taut without moving the throttle
linkage. (4) Install the snap ring into the groove
posi-
tioned second from the insulator.
(5) Depress the throttle pedal and check that the
throttle valve opens fully and returns to the idle
position when the pedal is released. (6) On 1.6 liter engines, install the air
cleaner
assembly.
7. ELECTRONIC COMPONENTS
NOTE: Before proceeding with any of the
operations in this section, refer to the Ser-
vice Precautions and Procedures heading.

TO CHECK IGNITION SYSTEM
(1) Perform the test procedure described in the
Roadside Trouble Shooting section. Repair or renew
components as necessary. (2) Perform the self diagnosis test procedure as
previously described and rectify any faults. If there is
no spark, proceed as follows. (3) Disconnect the 4 pin wiring connector from
the distributor and check for spark at a spark plug
high tension lead using the test spark plug. If there is a spark, renew the pickup coil in the
distributor.

If there is no spark, proceed as follows.
(4) Connect the coil high tension lead to the test
spark plug and check for spark.

If there is a spark, check the distributor cap and
rotor for cracks and moisture. Repair or renew as
necessary.

If there is no spark, proceed as follows.
(5) Disconnect the 2 pin wiring connector from
the distributor. (6) With the ignition switched On. measure the
voltage at terminals A and B on the distributor 2 pin
wiring connector. If the voltage at terminal B only is under 10 volts,
check the wiring harness for continuity between
terminal B on the distributor 2 pin wiring connector
and terminal 2 on the black ignition coil wiring
connector. Repair or renew the wiring harness as
necessary. If no fault is found, renew the ignition coll.

If the voltages at both terminals is under 10 volts,
check the wiring harness between terminal A on the
distributor 2 pin wiring connector and terminal 1 on
the black ignition coil wiring connector for continuity.
Also check the fuel pump fuse and the wiring harness
between the ignition switch and the ignition coil.
Repair or renew the wiring harness as necessary.

If the voltage at both terminals is 10 volts or
more, proceed as follows.

(7) Connect the 2 pin wiring connector to the
distributor. (8) With the ignition switched On, measure the
voltage at the tachometer signal wire.

Illustration identifying the 2 and 4 pin distributor wiring
connector terminals.
If the voltage is under 1 volt, check the tacho-
meter signal wire for continuity from the ignition coil.
Repair or renew the wiring harness as necessary.

If the voltage is 1-10 volts, renew the distributor
control module. If there is still no spark, renew the
ignition coil also.

If the voltage is over 10 volts, proceed as follows.
(9) With the ignition switch in the Start position,
check for voltage at the tachometer signal wire using
a test lamp.

If the test lamp flashes, replace the ignition coil
with a known serviceable un it. If there is still no
spark, install the original coil and renew the control
module.

If the test lamp remains illuminated, proceed as
follows.

(10) Remove the distributor cap and disconnect
the pickup coil wiring co nnector from the control
module. (11) Connect a voltmeter between the tachometer
signal wire and earth. (12) Connect the lead of a test lamp to a power
supply of 1.5-8 volts. (13) With the ignition switched On, momentarily
connect the probe of the test lamp to terminal P on
the control module and note the voltage. The voltage
should decrease to 7-9 volts. If there is no voltage decrease, check the control
module earth. If the earth is satisfactory, renew the
control module.

If the voltage decreases , proceed as follows.
(14) Check for spark at the coil high tension lead
as the test lamp is disconnected from terminal P on
the control module.

If there is no spark, proceed to operation (15).
If there is a spark, check that the steel rotor on the
distributor shaft is magnetized. If it is not renew the
distributor shaft assembly.

If the steel rotor is magnetized, check that the
resistance between the pickup coil leads is 500-1 500
ohms and not earthed. Renew the pickup coil as
necessary.

(15) Renew the ignition coil and check for spark.
If there is no spark check the coil high tension

lead. If no fault can be found, renew the control
module.

108 Fuel and Engine Management


Installed view of the control unit with the passengers seat removed.
(2) Secure the Mem-Cal unit retaining clips.
Ensure that the clips locate into the Mem-Cal unit. (3) When installing a new control unit, transfer
the identification and bar code label to the new
control unit. (4) Ensure that the control unit wiring connec-
tors are securely installed to the control unit. (5) Activate the self diagnosis codes. If code 51
is displayed or the Check Engine warning lamp is
constantly illuminated, the Mem-Cal unit is not fully
installed. If the Mem-Cal uni t is installed correctly, a
fault in the Mem-Cal unit is indicated. Renew the
Mem-Cal unit as previously described.
To Check Power Supply and Earth Circuit

(1) Disconnect the control unit wiring connec-
tors and check for voltage at terminals B1 and C16.

If there is no voltage check the fusible link which
is located third from the front in the fusible link
connecting block. If the fu sible link is serviceable,
repair the open circuit in the wiring harness.

(2) Check for continuity to earth on terminals
A12, D1, D6 and also D3 and D10 on 1.8 liter
engines.

If there is no continuity check the earth connec-
tions at the right hand rear cylinder head bolts. If the
connections are clean and secure, repair the open
circuit in the wiring harness.

MEM-CAL UNIT
To Test - Code 51

If code 51 is displayed during the self diagnosis
test procedure, pr oceed as follows:

(1) Check that the Mem-Cal unit is fully inserted
in the control unit. (2) Erase the fault code memory and retest for
fault codes. (3) If code 51 is still displayed, renew the
Mem-Cal unit.
(4) Erase the fault code memory and retest for
fault codes. (5) If code 51 is still displayed, renew the control
unit.
To Remove and Install

The Mem-Cal unit is incorporated within the
control unit. Refer to the previous heading for the
removal and installation procedure.

FUEL PUMP AND EGI RELAYS
To Remove and Install
(1) Disconnect the negative battery terminals.
(2) Remove the fuse panel cover which is lo-
cated adjacent to the steering column under the
instrument cluster. (3) Remove the spare fuse holder from the fuse
panel and remove the releva nt relay from the connec-
tor. Installation is a reversal of the removal procedure.


View showing the location of the EGI and fuel pump
relays.
To Test Relays
NOTE: When testing the fuel pump relay
circuit ensure that th e EGI relay is service-
able and installed to the relay connector

(1) Remove the relevant relay as previously
described. (2) Using an ohmmeter, check for continuity
between terminals 1 and 2, and 3 and 5. Continuity should exist be tween terminals 1 and 2
but should not exist between terminals 3 and 5.

(3) Using suitable jumper leads, apply 12 volts
to terminal 1 and connect terminal 2 to a good earth
point. (4) Connect the ohmmeter between terminals 3
and 5. Continuity should exist. If continuity does not
exist, renew the relay.

Fuel and Engine Management 109


Diagram showing the identification of the relay and the relay connector terminals.
To Test Relay Circuits
(1) Remove the relevant relay as previously
described and connect the ne gative battery terminal.
(2) Connect a test lamp to earth and probe the
fuel pump relay connector terminal C or the EGI relay
connector terminal A. With the ignition switched On
the test lamp should light. If the test lamp does not light check the fuel pump
fuse and the wiring harness for continuity between the
ignition switch and the fuel pump relay connector
terminal C or EGI rela y connector terminal A.

(3) With the ignition remaining switched On,
connect the test lamp between the fuel pump relay
connector terminals C and B or the EGI relay
connector terminals A and B.

If the test lamp does not light, repair the open
circuit between terminal B and earth.

(4) When checking the EGI relay circuit, pro-
ceed to operation (9).

When checking the fuel pu mp relay circuit pro-
ceed as follows.

(5) Probe the relay connector terminal A with a
test lamp to earth. Switch the ignition On and note the
test lamp.

If the test lamp lights for 2 seconds, proceed to
step (7).

If the test lamp does not light as specified, proceed
as follows.

(6) Switch the ignition Off and backprobe the
control unit wiring connector terminal A1 with a test
lamp to earth. With the ignition switched On the test
lamp should light as previously described.

If the test lamp does not light as described, renew
the control unit.

If the test lamp does light as described, locate the
open circuit or short in the wiring harness between the
control unit wiring connector terminal Al and the
relay connector terminal A. Repair or renew the
wiring harness as necessary.

(7) With the ignition switched Off connect a
jumper lead between the relay connector terminals C
and D. (8) Switch the ignition On and listen for the
operation of the fuel pump. It should be possible to
feel vibrations in the fuel return hose. If the fuel pump is operating, the fuel pump relay
circuit can be considered serviceable.

If the fuel pump is not operating, check the wiring
harness for continuity between the fuel pump wiring
harness connector, the fuel pump relay connector
terminal D and earth. If no fault can be found, renew
the fuel pump.

(9) Probe the relay connector terminal C with a
test lamp to earth. The test lamp should light.

If the test lamp does not light, locate the open
circuit between the battery and terminal C. Check the
fusible link which is located third from the front in the
fusible link connecting block.

(10) Connect a jumper lead between the relay
connector terminals C and D and backprobe the
control unit wiring connector terminal A6 with a test
lamp to earth.

If the test lamp lights, the EGI relay circuit can be
considered serviceable.

If the test lamp does not light locate the open
circuit between the contro l unit wiring connector
terminal A6 and the relay connector terminal D.
Repair or renew the wiring harness as necessary.

COOLANT TEMPERATURE SENSOR
To Test — Codes 14 and 15
(1) Erase the self diagnosis code memory as
previously described. (2) Start and run the engine at idle speed for 60
seconds or until the ECM warning lamp lights.
(3) Stop the engine, switch the ignition On and
connect a jumper lead between terminals A and B on
the diagnostic link connect or. Note any fault codes
displayed. If codes 14 or 15 are displayed, proceed to
operation (4).

If codes 14 or 15 are not displayed, but were
displayed when the self diagnosis test procedure was


View showing the location of the coolant temperature
sensor. 1.6 liter engine.

114 Fuel and Engine Management
(6) Check the vehicle for the following:
(a) Low fuel pressure.
(b) Contaminated fuel.
(c) Vacuum leaks at the inlet manifold, engine
vacuum hoses and engine ventilation hoses. (d) Exhaust manifold leaks before the oxygen
sensor. (e) Correct MAP sensor operation.
(f) Blocked oxygen sensor metal vent cover eg.
plugged with mud etc. (g) Fuel injectors) partially blocked. Refer to a
fuel injection specialis t or a Nissan dealer.
If the above items have been checked and no
faults have been found, a faulty oxygen sensor is
indicated. Renew the oxygen sensor, run the engine
and ensure that no fault codes are set.

To Test — Code 45
(1) Run the engine until normal operating tem-
perature is attained. (2) With the ignition switched Off, connect a
jumper lead between terminals B and A on the
diagnostic link connector. (3) Start and run the engine at approximately
1 600-1 800 rpm for 2 minutes and note the ECM
warning lamp. If the ECM warning lamp is on more than off or
flashes at the rate of twice per second, proceed to the
following operation.

If the ECM warning lamp flashes evenly at the
rate of once per second an intermittent fault is
indicated. Proceed as follows:

(a) Check for faulty wiri ng connections. Check
that all wiring connectors are clean and secure. (b) Check that all earth wires are secure.
(4) Switch the engine Off and disconnect the
oxygen sensor wiring connector. (5) Using a jumper lead, connect the oxygen
sensor wiring connector to a suitable engine earth. (6) Start and run the engine at 1 600-1 800 rpm
and note the ECM warning lamp.
If the ECM warning lamp extinguishes for at least
30 seconds, proceed to operation (7).

If the ECM warning lamp flashes on more than off
or flashes at the rate of twice per second, switch the
engine Off and disconnect the control unit wiring
connectors. Using an ohmmeter, check that there is no
resistance between the co ntrol unit wiring connector
terminal D6 and earth. Repair or renew the wiring as
necessary.

If no fault can be found in the wiring harness,
renew the control unit.

NOTE: The wiring harness for terminal D6
earths through the righ t hand rear cylinder
head bolt.

(7) Check the vehicl e for the following:
(a) High fuel pressure.
(b) Leaking injector(s).
(c) Faulty ignition wiring.
(d) Charcoal canister purge system blocked or
restricted.
(e) Faulty coolant temper ature sensor circuit.
(f) Faulty MAT sensor circuit (1.8 liter engine).
(g) MAP sensor operation.
(h) Throttle position sensor operation.

If the above items have been checked and no
faults have been found, a faulty oxygen sensor is
indicated.

Renew the oxygen sensor, run the engine and
ensure that no fault codes are set.

To Remove and Install
(1) If the engine is cold, run the engine for
approximately two minutes to allow easy oxygen
sensor removal. (2) Disconnect the negative battery terminal and
the oxygen sensor connector.

View of the oxygen sensor removed from the exhaust
manifold.
(3) Remove the exhaust manifold heat shield
retaining bolts and remove the heat shield from the
engine.
(4) Remove the oxygen sensor with a short ring
spanner using care not to damage the sensor wire. Installation is a reversal of the removal procedure
with attention to the following points:

(1) When installing a sensor that has previously
been removed, coat the sen sor threads with anti-seize
compound. Nissan recommend a mixture of liquid
graphite and glass beads. (2) Install the sensor and tighten to the specified
torque. (3) Connect the electrical connector ensuring
that the wiring is secured away from the exhaust. (4) Install the heat shield and tighten the retain-
ing bolts securely. On 1.6 liter engines, ensure that the hot air inlet
tube is located correctly be tween the heat shield and
the air cleaner housing.

(5) Start the engine and check for leaks.
VEHICLE SPEED SENSOR
To Test - Code 24

(1) Check the fuel pump and meter fuses. If the
fuses are serviceable, proceed to operation (5). If a
fuse is blown, rectify the cause and renew the fuse.

117
EMISSION CONTROL
INTRODUCTION
To reduce the output level of the three primary
automotive emissions, carbon monoxide (CO), hydro-
carbons (HC) and oxides of nitrogen (NOx), and thus
comply with legislation on the maintenance of clean
air, several different emissi on control systems are used
in the Pulsar range of vehicles covered by this manual.

The systems will be discussed under the headings
( 1 ) Crankcase Ventilation System, (2) Evaporative
Control System, (3) Air Preheat System — 1.6 Liter
Engine and (4) Exhaust Control System.

1. CRANKCASE VENTILATION SYSTEM
DESCRIPTION
The crankcase ventilation system is of the closed
type and is designed to prevent crankcase vapors
being emitted into the atmosphere. Crankcase
vapors are caused by gases escaping past the piston
rings into the crankcase during the combustion pro-
cess.

The crankcase vapors are collected in the cam-
shaft housing from the cra nkcase via the various oil
drain passages and the pipe from the side of the
crankcase.


The crankcase vapors are then drawn into the
engine via a branched hose connected to the camshaft
housing oil baffle and the throttle body (1.8 liter
engines) or inlet manifold (1.6 liter engines).

At idle speed, vapors are drawn through the
small branch of the hose and into the engine.

As the engine speed increases, vapors are also
drawn into the engine via the main hose.

TO SERVICE THE SYSTEM
(1) At intervals of 40 000 km, disconnect the
small engine ventilation hose from the throttle body
or inlet manifold and check that the metering orifice
is not blocked.

If necessary, clean the orifice using compressed air
and solvent.

(2) Disconnect all the engine ventilation hoses
and check for blocking, collapsing and deterioration.
Renew the hoses as necessary.

2. EVAPORATIVE CONTROL SYSTEM
Special Equipment Required:
To Test Purge Valve — Hand vacuum pump
DESCRIPTION
The evaporative control system reduces the
amount of hydrocarbons emitted to the atmosphere
through fuel evaporation.

The vehicles covered by this manual use an
absorption regeneration system to reduce vapor loss.
The system utilizes a canister of activated charcoal to
trap and hold the fuel vapors until they can be fed
into the induction system for burning in the combus-
tion chambers.

The basic components of the evaporative control
system are a fuel tank with a sealed filler cap, a
charcoal canister with a pur ge control valve, a fuel
check valve and pipes a nd hoses to connect the
various components.

NOTE: The fuel tank filler cap is not vented
to the atmosphere but is equipped with a one
way relief valve to prevent a vacuum form-
ing in the fuel tank.
View of the engine ventilation hoses and pipe. 1.8 liter
engine.

118 Emission Control


Installed view of the charcoal canister.
When the engine is at rest, fuel vapor through
evaporation gradually fills the air space in the fuel
tank. The sealed filler cap pr events the escape of this
vapor and pressure builds up within the system,
forcing the vapor to flow into the charcoal canister
which is located in the engine compartment beneath
the windscreen wiper motor.

The fuel check valve prevents liquid fuel entering
the charcoal canister when the fuel tank is full or the
vehicle is parked on a steep incline. When the engine
is running, the vapor is drawn via a hose from the
charcoal canister to the throttle body and burnt in the
combustion chambers.

TO RENEW CHARCOAL CANISTER
(1) Suitably mark and disconnect the hoses from
the canister. (2) Release the retaining spring and remove the
canister from the engine compartment. Installation is a reversal of the removal procedure.

TO RENEW FUEL CHECK VALVE
(1) Disconnect the negative battery terminal.
(2) Raise the rear of the vehicle and support it
on chassis stands. Remove the left hand rear wheel. (3) Drain the fuel from the fuel tank using a
hand pump or a suitable siphon. Do not siphon fuel
using the mouth.
(4) Remove the hoses from the check valve.
(5) Squeeze the retaining clip and remove the
check valve from the mounting bracket. Installation is a reversal of the removal procedure.

TO SERVICE THE SYSTEM
(1) Inspect the vacuum lines and connectors for
signs of leakage, cracks and deterioration and renew
as necessary. (2) Remove the fuel tank cap and check that a
slight resistance is felt, when vacuum is applied to the
one-way relief valve in the centre of the cap. Renew the fuel tank cap if no resistance is felt or
if the valve is blocked.

(3) Inspect the fuel tank cap seal for deteriora-
tion. Renew as necessary.

Installed view of the fuel check valve as seen with the
left hand rear wheel removed.
Check the fuel filler cap seal for damage.
23Q/LDZ GAUGE
Line drawing showing a hand vacuum pump.